Theo Walcott will have a scan on Monday to ascertain the damage done to his knee late in Saturday’s 2-0 derby win over Tottenham. Should the test reveal ligament damage, as Arsène Wenger fears, the Arsenal manager may be forced into the transfer market.

Wenger initially hoped Walcott had merely taken a kick but the indications are that his injury is more serious. With Nicklas Bendtner also out for a month, Arsenal are now overly dependent on Olivier Giroud.

Though the French striker has been absent with an ankle injury and illness, he expects to be back for Arsenal’s next match, at Aston Villa next Monday, but with the Gunners in contention for their first league title since 2004, Wenger must decide whether to take the plunge.

However, he has said: “All the big players are at big clubs at the moment and unless you have a club in a desperate financial situation it will be difficult.”

With Valencia, perhaps the most impecunious of all the big clubs, having already been pillaged, the options are few.

Walcott’s injury means it would have no material effect were he to be banned by the Football Association for provocatively signalling the scoreline to Tottenham fans while being carried off. A suspension is unlikely.

It was not just verbal abuse that Spurs supporters hurled at Walcott. Even before his gesture, coins rained down on him and the medical staff while he was being tended on the pitch. Spurs may thus face an FA investigation. As Tim Sherwood, Spurs’ head coach, said when informed of the incident: “There is a problem if that happened.”

It was the least of Sherwood’s worries after a match that punctured much of the optimism that has returned to Spurs since his appointment. After a promising opening they were beaten with surprising ease by an Arsenal side which dominated midfield. Sherwood insisted, despite all the available evidence, that he had not played 4-4-2 but “just had 11 numbers on the field and tried to rotate and fill up every area of the field”.

Nevertheless, in the area that mattered Mousa Dembélé and full debutant Nabil Bentaleb were outnumbered and outplayed and both may be in trouble for aggressive behaviour towards Jack Wilshere and Nacho Monreal respectively that revealed their frustration.

The impressive Serge Gnabry was given too much space to set up Santi Cazorla for the opening goal, then Danny Rose handed Tomas Rosicky the second.